(1) Field of the Invention
This invention relates to deferred actuated batteries, and more particularly to an improved deferred actuated battery including bipolar electrodes.
(2) Description of the Prior Art
Battery requirements for marine data systems vary from a few milliwatts for CMOS instrumentation to several tens of kilowatts for the operation of a mini autonomous underwater vehicle (AUV). Nonaqueous lithium cells and zinc-based primary cells, as well as nickel-cadmium and lead-acid batteries, are currently used. Safety and the corrosive nature of the electrolyte and/or some cathode materials used in such power sources dictate that cells and batteries be well sealed to prevent leakage and/or rupture during storage and use. Lithium batteries use hermetic seals with safety vents and a fuse. Alkaline cells are rendered leakproof by suitable double crimp joints. Lead-acid cells use a gelled electrolyte to prevent spillage of the electrolyte. Such techniques have minimized the hazards of handling and use, however at the expense of costs. Sealed cells require a "pressure hull" enclosure for deep sea application and thus use of a pressure hull significantly reduces energy density and concomitantly increases usage cost. Other types of power cells used in undersea applications are water activated magnesium batteries with a bipolar configuration as open cells. A magnesium anode and a metal halide-based cathode allows the use of sea water as the electrolyte and do not require a pressure hull housing for deep sea applications.
Deferred actuated batteries, such as silver chloride-magnesium batteries using seawater as an electrolyte have been used for years, and are expensive being based upon the use of a precious metal, i.e. silver. Subsequent developments centered on non-silver containing sea water actuated batteries, e.g. U.S. Pat. Nos. 3,432,350 and 3,462,309 to Wilson based upon a magnesium anode-inert metal cathode type of a serial flow type configuration provided limited usages as well as extensive electrical circuitry including tunnel diode inverters t provide useful voltage levels. In U.S. Pat. No. 4,185,143 to Brit et al., there is disclosed a water actuated battery based upon metal/organo halogen couples having anode and cathode members of planar form with a porous insulating member sandwiched therebetween where the cell is provided with electrolyte access passageways extending around the periphery of the cathode member whereby electrolyte flowing in the passageway access the whole peripheral edge region of the cathode reactant material.